This men's Polar model #S 120 heart rate monitor has a lot of features although a little pricey as compared with other brands with similar features. Unless you use this for swimming the chest strap transmitter need not be totally waterproof. Because of this feature, the chest strap transmitter battery is not replaceable. The battery life is good for up to 2500 hours before you have to replace the transmitter. This system uses a uncoded wireless transmission between the chest strap transmitter and the wrist watch receiver. It is possible to replace the transmitter when the time comes with one of a different brand with a replaceable battery system. The receiver battery is replaceable but for the warranty to be in effect you are not allowed to open the watch for battery replacement. It has to be done in an authorized Polar Service Center. To replace the battery on the receiver, all you need to do is remove four screws on the back and lift the cover and then lift the clip over the battery. The battery can then be pried up with a little screwdriver. When replacing the cover be sure the o-ring gasket is in place in the groove and clean to maintain the water resistant feature. I did open mines anyway to fix the hard to press buttons. Before the repair, I had to press real hard on the button to get it to respond. It works great after the repair.

The heart rate reading is fairly accurate when there's no interference. I wasn't able to get a reading while doing jumping jacks. It does work with other exercises like jogging and weight lifting. It also doesn't work too well when you have severe heart arrhythmia like in my case(PVC). With minor arrhythmia it still able to get accurate heart rate reading. It also, unable to get a heart rate reading anywhere near an underground transformer vault under the sidewalk. It also doesn't work to well when you near another person with a heart rate monitor. The chest strap transmitter is very comfortable to use. The black plastic watch receiver is kind of big and bulky. You can use this to check your recovery time right after exercise. It comes with multiple timers, setting for three heart rate zones, memory for only one exercise set, an independent, count-down or count-up timer, a maximum heart rate setting based on your birthday, a time setting with an independent alarm, an optional capability of downloading the exercise set data to your computer and exercise set viewing. For the downloading capability you have to buy this optional interface from Polar to hook on to to your computer. I was also able to get a heart rate reading by holding the chest strap transmitter at the electro part between my left and right hands. This is useful right after you take your blood pressure with a non electronic blood pressure cuff when you are not wearing the heart rate monitor. Unfortunately, this heart rate monitor does not come with a backlight for nighttime viewing while exercising. For those of you who are really in to exercising, it might be better to pay a little more and buy a model that has both a backlight and transmission coding to avoid interference. Although, I think when it comes to big electrical equipment interference it may still be a problem with a coded system. Such as near high tension electrical lines and big transformers.

I will update this review when I learn more about the shortcomings and features of this heart rate monitor in the future (Update 08-18-05) I take it back, I was able to get a reading while doing jumping jacks with application of little conductive gel on the chest strap. It's the kind of gel use for applying on the Electros of an electronic muscle stimulation device.

Recommended: Yes